TM 1-1510-225-10 2-119 F3 The controls and indicators for the standby attitude indicator back up battery power system are located on the audio control panel. (1)   Standby   Horizon   Power   Warning   Horn Silence  Switch.    The  standby  horizon  power  warning horn   may   be   silenced   by   pressing   a   push-button switch placarded HORN SILENCE  R. (2)   Standby  Horizon  Power  Control  Switch. A  switch  placarded  ON  /  OFF  /  TEST  controls  the standby horizon power system. (3)   Standby     Horizon     Power     Annunciator. The    standby    horizon    power    system    annunciator, placarded AUX ARM / AUX ON / AUX TEST, is used to monitor functional state of the system. 2-82.  FREE AIR TEMPERATURE (FAT) GAUGE  R . A digital free air temperature gauge is located on the   left   cockpit   sidewall.      Temperature   is   normally displayed   in   C,   but   pressing   a   push-button   switch placarded  PUSH  FOR  °F  will  change  the  display  to degrees Fahrenheit. 2-83.  STANDBY MAGNETIC COMPASS. Inaccurate    indications    on    the    standby magnetic compass will occur while windshield  heat,  air  conditioning,  or  EFIS are being used or the sun visors are in the front position. The  standby  magnetic  compass,  located  below the overhead control panel, Figure 2-31, is used in the event   of   failure   of   the   compass   system,   and   for instrument  cross  check.    Readings  should  be  taken only  during  level  flight  since  turning  or  acceleration may  introduce  errors.    A  compass  correction  chart, indicating deviation factors, is located on the magnetic compass. 2-84.  VERTICAL SPEED INDICATORS. a.   Description R.  The vertical speed indicators are incorporated on both pilot and copilot’s altitude/vertical     speed     indicators.          The     face     is placarded   VERTICAL   SPEED   UP   /   DOWN.      The range  of  the  instrument  is  from  0  to  6,000  feet  per minute,   the   first   1,000   feet   graduated   in   100   fpm increments. b.  Description     T3.          The     pilot’s     VSI     is incorporated  into  the  TVSI  TCAS  II   indicator.    The range  of  the  instrument  is  from  0  to  6,000  feet  per minute, with the first 1,000 feet graduated in 100 fpm increments and the remainder in 500 fpm increments. The copilot's VSI is placarded VERTICAL SPEED UP /  DOWN,  The  range  of  the  instrument  is  from  0  to 3,000 feet per minute, the first 1,000 feet is graduated into 100 fpm increments.  The remainder is graduated in 500 fpm. c.   Description F3. The vertical speed indicators are mounted on both sides of the instrument panel.  The face is placarded VERTICAL SPEED UP / DOWN.  The range of the instrument is for 0 to 4,000 feet  per  minute,  with  the  first  2,000  feet  graduated  in 100  fpm  increments  and  the  remainder  in  250  fpm increments. 2-85.  MISCELLANEOUS INSTRUMENTS. a.   Warning  Annunciator  Panel.    The  warning annunciator    panel,    Figure    2-41,    located    near    the center   of   the   instrument   panel   in   the   glareshield, contains  red  fault  annunciators.    Illumination  of  a  red fault annunciator signifies the existence of a hazardous  condition  requiring  pilot  attention.    Table 2-13  lists  the  red  fault  annunciators,  and  the  causes for their illumination. Figure 2-41.  Warning Annunciator Panel  R  (Sheet 1 of 2) WARNING